Bohrsystem mit exzentrischem Stabilisator mit einstellbarem Durchmesser der Flügel

A drilling assembly includes an eccentric adjustable diameter blade stabilizer having a housing (12) with a fixed stabilizer blade (30) and a pair of adjustable stabilizer blades (40,42). The adjustable stabilizer blades (40,42) are housed within openings (60,62) in the stabilizer housing (12) and have inclined surfaces (88,90) which engages ramps (78,80) on the housing (12) for camming the blades (40,42) radially upon their movement axially. The adjustable blades (40,42) are operatively connected to an extender piston (104) on one end for extending the blades and a return spring (110) at the other end for contracting the blades. The eccentric stabilizer also includes one or more flow tubes (44) through which drilling fluids pass that apply a differential pressure across the stabilizer housing (12) to actuate the extender pistons (104) to move the stabilizer blades (40,42) axially upstream to their extended position. The eccentric stabilizer is mounted on a bi-center (202) which has a eccentric reamer (208) section and a pilot bit (206).